The Right Diet for Your Body

Scale not budging? Your DNA may require a different diet.

by Joan Raymond

Photograph: Jacob Wackerhausen

For decades, if not centuries, doctors have searched for the one diet that will help people maintain a healthy weight. But the latest thinking points to a different goal: finding not the best eating plan but the best eating plan for you. You’ve probably already noticed that when it comes to dieting, what works for your best friend—say, a low-carb plan—doesn’t necessarily work as well for you. But while that might have seemed like a purely personal preference, researchers now believe that it’s more a matter of biology.

Last year, for instance, Stanford University researchers gave genetic tests to 133 overweight and obese women who had already participated in a yearlong study in which they had been randomly assigned one of four popular low-carb or low-fat diets. The tests, which focused on three genes that affect how efficiently the body metabolizes fat and carbohydrates, determined which variations of those genes each woman possessed. The researchers then reanalyzed the original study data and found that women whose diets had matched up well with their low-fat or low-carb gene profiles lost 5.3 percent of their body weight, while those whose diets didn’t suit their biology dropped only 2.3 percent.

At Canyon Ranch, Mark Liponis, MD, the corporate medical director, has been conducting his own research on more than 6,000 patients for an upcoming book. We talked with Liponis, author of UltraLongevity, about how understanding your weight-loss ­genetics—?by looking at your body type—?can up your chances of dropping pounds.

Why would genetic differences play a role in our weight?
Humans have evolved in different environments around the globe, with different food supplies readily available. Maybe in one environment, people ate a lot of salmon and other fish and over time became more efficient at metabolizing protein, and maybe in another they ate a lot of corn and wheat and so got better at handling carbohydrates.

Would you recommend getting a genetic test to figure out which diet may work best for you?
No, not at this point. There are probably easier solutions than testing every person’s genes.

Such as what?
I think we are going to learn a lot more about how a person’s ­phenotype—her observable physical characteristics, which are influenced by her genetic structure—correlates with how she gains and loses weight. I think people are going to stratify into one of three groups based on how they look when they become heavier: those with big bellies, those with big butts and those who get big all over. And then we can design diets to fit each phenotype.

What have you learned from your work at Canyon Ranch?
If we put a person on a diet that matches her body type, she not only loses more weight but feels full most of the day and does not have trouble staying on that eating plan. We also see improvements in blood parameters, such as blood sugar levels and cholesterol measures.

So what type of diet seems to work best for specific body types?
Those with big bellies do well on a low-carbohydrate, low-glycemic diet. This kind of diet emphasizes meat and dairy products, which generally produce small fluctuations in blood glucose and insulin, as well as carbohydrates that contain a lot of fiber, such as bran cereals. On the other hand, people with big butts tend to do better with low-fat, high-carb diets—eating plans that often center on vegetables and grains while minimizing red meat. And those who are large all over seem to do well with a Mediterranean diet—one that is rich in fruits and vegetables, whole grains, nuts and seeds, legumes and healthy fats like olive oil.